Clinical trials should be carried out sooner for H7N9 vaccine products, but it's not necessary to conduct large-scale public immunization, experts said.
Researchers at the Shanghai Public Health Clinical Center have recently developed a genetic vaccine against H7N9 and are applying for it to undergo clinical trials.
On Jan 7, Hualan Biological Engineering Inc, in Henan province, announced on its website it had finished the preclinical study of its H7N9 vaccine products and that it is waiting for the China Food and Drug Administration to approve of its application for clinical trials of the vaccine.
But the CFDA has not yet approved clinical trials on any H7N9 vaccine products, said Shu Yuelong, director of the Chinese National Influenza Center.
"How long it takes before we get a reply depends on where we are on the waiting list and whether the documentation we filed is fully prepared," said Liu Peicheng, an official at Sinovac Biotech Ltd in Beijing.
The company announced on its website on Jan 29 that it had filed an application of clinical trials for its H7N9 vaccine products.
Liu said it's possible that if H7N9 cases were to flare, the testing process would accelerate.
In 2009, when human infections of H1N1 were frequently reported, the CFDA raised the priority of H1N1 vaccine product assessments, shortening waits for testing and streamlining their path to the market.
"It's better that clinical trials (for H7N9 vaccine products) start sooner because it takes time to complete the testing," said Shu from the influenza center.
New H7N9 infection cases continue to emerge.
A 53-year-old man in Jiangsu province was diagnosed with H7N9 on Saturday. The provincial health bureau said he transported two truckloads of chicken feathers from butchered chickens before he got sick.
A 75-year-old woman diagnosed with H7N9 in Nanjing on Jan 30 died on Friday despite emergency treatment, the bureau said.
However, Shu said there is no need for a large-scale immunization because the infections remain sporadic and the virus doesn't transmit effectively among human.
He Jianfeng, chief expert at the Guangdong province Center for Disease Control and Prevention, said it is not cost-effective to carry out large-scale immunization right now. But he emphasized that an H7N9 vaccine could help guarantee large-scale immunization when the virus is found to be able to transmit among human effectively.
He doesn't expect the virus to mutate so much as to make the technology to produce H7N9 vaccines ineffective.
"As long as it remains to be H7N9, the mutation will not require much change in the technology for us to produce a vaccine against it," he said. "We'll just need a new strain of H7N9 virus to produce the vaccine with the same technology, just like we use new strains of other kinds of flu virus to produce effective vaccines every year, because the viruses, though they are the same ones, become slightly different from year to year."
